A data transfer amount of a wireless network has been rapidly increased in recent years. It is because various devices, e.g., a smart phone, a tablet personal computer (PC), or the like, that require machine-to-machine (M2M) communication and a high data transfer amount have been introduced and distributed. To satisfy the required high data transfer amount, a carrier aggregation (CA) technique, a cognitive radio (CR) technique, or the like for effectively using more frequency bands and a multiple antenna technique, a multiple base station cooperation technique, or the like for increasing data capacity within a limited frequency have recently drawn attention.
In addition, the wireless network has been evolved in a direction of increasing density of nodes capable of accessing to an area around a user. Herein, the node implies an antenna (or antenna group) which is separated from a distributed antenna system (DAS) by more than a certain distance. However, the node is not limited to this definition, and thus can also be used in a broader sense. That is, in a broad sense, the node may be a pico-cell eNB (PeNB), a home eNB (HeNB), a remote radio head (RRH), a remote radio unit (RRU), a relay, a distributed antenna (group), etc. A wireless communication system having nodes with higher density can provide higher system performance by cooperation between the nodes. That is, better system performance can be achieved when one base station controller manages transmission and reception of respective nodes and thus the nodes operate as if they are antennas or an antenna group for one cell, in comparison with a case where the respective nodes operate as an independent base station (BS), advanced BS (ABS), Node-B (NB), eNode-B (eNB), access point (AP), etc., and thus do not cooperate with each other. Hereinafter, a wireless communication system including a plurality of nodes is referred to as a multi-node system.
If each node of the multi-node system performs scheduling and handover by having its own identifier (ID), such a multi-node system can be regarded as a multi-cell system. If a coverage of each cell (i.e., node) is overlaid in the multi-cell system, such a multi-cell system is called a multi-tier network.
In the multi-node system, a BS may transmit and receive data by selecting a plurality of nodes, or a user equipment (UE) may transmit and receive data with respect to the plurality of nodes. In this case, a channel established between the UE and each node does not have a uniform channel state. As such, for a case where a channel state is not uniform, there is a need for a method capable of using the same modulation and coding scheme (MCS) in each node. In addition, if a different MCS is used for each node, there is a need for a method capable of maximizing link efficiency.